Light fixture with peripheral cooling channels

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a nonprovisional of U.S. Provisional Application No. 61/545,307, filed Oct. 10, 2011, and titled Light Fixture with Peripheral Cooling Channels, which is herein entirely incorporated by reference.

BACKGROUND

The present invention relates to light fixture cooling features, and particularly, to providing a light fixture with external surface features to facilitate cooling.

Managing the temperature of light sources in a light fixture is generally important to performance and longevity. This is particularly true with newer highly efficient lighting technology, for example, light sources such as LEDs or laser diodes. LEDs are generally selected to maximize the light output for a given power consumption at a reasonable cost. Because LED light sources operate at a much lower temperature than typical incandescent light sources, less energy is wasted in the form of heat production. However, LEDs tend to be more sensitive to operating temperature and lower operating temperatures also provide a much smaller temperature difference between the LED and the ambient environment, thus requiring greater attention to thermal management to transfer and dissipate any excess heat generated by the LED driver and emitter so that the design operating temperature for the components are not exceeded.

As temperatures rise, the efficacy of the LED is reduced, reducing the light output, and reducing the lifespan of the LED. LED lighting fixtures generally include both LED drivers and LED emitters. To facilitate dissipation of heat, convection, conduction, and radiation are available modes of heat transfer. For LED light fixtures, dissipation of heat by conduction is often provided by one or more LED packages being mounted on a heat sink. The heatsink is generally integral with or thermally coupled with the light housing, which often includes external cooling fins to further facilitate the dissipation of heat from the light fixture by convection and radiation.

Many prior designs seeking to address these concerns provides a set of fins forming vertical airflow channels extending radially around a light emitter and driver housing; however, the fins forming the airflow channels only abut vertical edges of the housing.

Therefore, it is desirable to provide a lighting fixture design in a unitary fixture that maximizes cooling by thermal convection for the light housing, including convection from horizontal surfaces of the housing, and shields the cooling features from as many viewing angles as practical. Additionally, for some lighting fixture designs, it is also desirable to minimize thermal conduction between emitter and driver housings.

SUMMARY

The present invention may comprise one or more of the features recited in the attached claims, and/or one or more of the following features and combinations thereof.

An illustrative light fixture includes an emitter housing and airflow cooling channels. The airflow cooling channels are defined in the space between opposite edges of the emitter housing and a rim around the periphery of at least the opposite edges of the emitter housing. The airflow channels are further defined by fins spanning between the rim and opposite edges and spanning across a side of the housing opposite the illumination side.

An illustrative embodiment of a light fixture for a light emitter includes an emitter housing; an illumination side of the emitter housing, the light emitter projecting light from the illumination side; an opposite side of the emitter housing, located opposite the illumination side; a first and second edge defined by the emitter housing, each of the first and second edges spanning between the illumination and opposite sides; a first rim positioned along the first edge of the emitter housing and spanning between the illumination and opposite sides; a second rim positioned along the second edge of the emitter housing and spanning between the illumination and opposite sides; and a first plurality of fins spanning between the first edge and the first rim, the first edge and the second edge, the second edge and the second rim, and the first rim and the second rim.

The light fixture can further include a plurality of airflow channels, each of the plurality of airflow channels defined between adjacent ones of the first plurality of fins, each of the plurality of airflow channels open to the illumination side of the emitter housing between the first rim and the first edge, extending across the opposite side of the emitter housing, and open to the illumination side of the emitter housing between the second rim and the second edge.

In one illustrative embodiment, the light fixture further includes a driver housing, the driver housing defining a front surface; and an airflow passage defined by a space between the opposite side of the emitter housing and the front surface of the driver housing; and wherein the first plurality of fins extend through the airflow passage. The light fixture can further include a second plurality of fins defined by the driver housing. The first plurality of fins and the second plurality of fins can form a plurality of coplanar fins surfaces.

A plane formed across the first rim and the second rim can optionally not be intersected by the first plurality of fins. A plane formed across the first rim and the second rim can optionally not be intersected by the first edge or the second edge. The first plurality of fins can be in thermal conductivity with the light emitter.

The first rim and the second rim can be on opposite sides of the emitter housing. The first plurality of fins can be parallel with one another. The first plurality of fins can be evenly spaced. The light fixture can further include a top surface defined by the emitter housing, and the top edges of the first plurality of fins can be coplanar with the top surface of the emitter housing.

Another illustrative embodiment of a light fixture for a light emitter includes an emitter housing; an illumination side of the emitter housing, the light emitter projecting light from the illumination side; an opposite side of the emitter housing, located opposite the illumination side; a first and second edge defined by the emitter housing between the illumination and opposite sides; a first rim positioned along the first edge of the emitter housing; a second rim positioned along the second edge of the emitter housing; and a first plurality of fins spanning between the first edge and the first rim, across the opposite side of the emitter housing, and between the second edge and the second rim.

In one illustrative embodiment, the light fixture further includes a driver housing, the driver housing defining a front surface; and an airflow passage defined by a space between the opposite side of the emitter housing and the front surface of the driver housing; and wherein the first plurality of fins extend through the airflow passage. The light fixture can further include a second plurality of fins defined by the driver housing. The first plurality of fins and the second plurality of fins can form a plurality of coplanar fins surfaces.

Another illustrative embodiment of a light fixture for a light emitter, includes a first housing; an illumination side of the first housing, the light emitter projecting light from the illumination side; an opposite side of the first housing, located opposite the illumination side; a first and second edge defined by the first housing between the illumination and opposite sides; a rim extending around at least two opposite edges of the first housing; a first plurality of fins spanning between the rim and the at least two opposite edges of the housing and across the opposite side of the first housing; and a plurality of airflow channels, each of the plurality of airflow channels defined between adjacent ones of the first plurality of fins, each of the plurality of airflow channels open to the illumination side of the first housing between the rim and a first one of the at least two opposite edges of the first housing, extending across the opposite side of the first housing, and open to the illumination side of the housing between the rim and a second one of the at least two opposite edges of the first housing.

In on illustrative embodiment the light fixture further includes a second housing, the second housing defining a front surface; and an airflow passage defined by a space between the opposite side of the first housing and the front surface of the second housing; and wherein the first plurality of fins extend through the airflow passage. The light fixture can further include a second plurality of fins defined by the second housing. The first plurality of fins and the second plurality of fins can form a plurality of coplanar fins surfaces.

Additional features of the disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figures in which:

<figref idref="DRAWINGS">FIG. 1</figref> is a bottom perspective view of a first illustrative lighting fixture according to the present invention;

<figref idref="DRAWINGS">FIG. 2</figref> is a front perspective cross-sectional view of the lighting fixture of <figref idref="DRAWINGS">FIG. 1</figref>, taken along section line <b>2</b>-<b>2</b> shown in <figref idref="DRAWINGS">FIGS. 3 and 4</figref>;

<figref idref="DRAWINGS">FIG. 3</figref> is a top view of the lighting fixture of <figref idref="DRAWINGS">FIG. 1</figref>;

<figref idref="DRAWINGS">FIG. 4</figref> is a side view of the lighting fixture of <figref idref="DRAWINGS">FIG. 1</figref>;

<figref idref="DRAWINGS">FIG. 5</figref> is a front view perspective view of a second illustrative lighting fixture according to the present invention;

<figref idref="DRAWINGS">FIG. 6</figref> is a side perspective cross-sectional view of the lighting fixture of <figref idref="DRAWINGS">FIG. 5</figref>, taken along section line <b>6</b>-<b>6</b> shown in <figref idref="DRAWINGS">FIG. 7</figref>; and

<figref idref="DRAWINGS">FIG. 7</figref> is a rear perspective view of the lighting fixture of <figref idref="DRAWINGS">FIG. 5</figref>.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

For the purposes of promoting and understanding the principals of the invention, reference will now be made to one or more illustrative embodiments illustrated in the drawings and specific language will be used to describe the same.

Referring to <figref idref="DRAWINGS">FIGS. 1-4</figref>, a first illustrative embodiment of a light fixture <b>30</b> according to the present invention is illustrated. The light fixture <b>30</b> includes a light source <b>32</b>, including an emitter <b>34</b> (<figref idref="DRAWINGS">FIG. 2</figref>; as used herein, “emitter” refers to a single emitter or an array of emitters) and a driver <b>36</b> (not shown; as used herein, “driver” refers to a single driver or an array of drivers), and an emitter housing <b>52</b>. For example, light source <b>32</b> may be, but is not limited to, an LED emitter <b>34</b> and associated driver <b>36</b>, as are typically used in the commercial lighting industry. For example, the associated driver <b>36</b> converts AC power to appropriate DC power and may also include additional LED power and control features.

The emitter housing <b>52</b> can be formed from, for example, die cast aluminum or an aluminum alloy. The emitter <b>34</b> can be thermally coupled and mounted to the emitter housing <b>52</b>. As it typical of commercial lighting fixtures, the emitter housing <b>52</b> may also include components that enclose the emitter <b>34</b> within emitter housing <b>52</b>, for example, including a light reflector <b>54</b>, lens <b>58</b>, and frame <b>60</b>. In the first illustrative embodiment of the light fixture <b>30</b>, the driver <b>36</b> (not shown) is also located within the emitter housing <b>52</b>.

Referring to <figref idref="DRAWINGS">FIGS. 2</figref>, <b>3</b>, and <b>4</b>, the emitter housing <b>52</b> defines an illumination side <b>70</b> from which the light source <b>32</b> projects light (for example, in the first embodiment defined by the frame <b>60</b> and lens <b>58</b>), an opposite surface or back side <b>71</b>, a left side edge <b>72</b>, and a right side edge <b>74</b>. The light fixture <b>30</b> also includes a rim <b>76</b> around the periphery of the light housing <b>52</b>, including a left rim <b>73</b>, a right rim <b>75</b>, a top rim edge <b>77</b>, a bottom rim edge <b>78</b>, and an interior surface <b>79</b>. In the first illustrative embodiment, the left rim <b>73</b> is spaced apart from the left side edge <b>72</b> of the housing <b>52</b>, the right rim <b>75</b> is spaced apart from the right side edge <b>74</b>, and the remainder of the rim <b>76</b> on front and rear sides contacts the housing <b>52</b>.

The light fixture <b>30</b> also includes a plurality of fins <b>90</b>, for example, in the first embodiment defined at least in part by the back side <b>71</b> of the emitter housing <b>52</b>, thus, the plurality of fins <b>90</b> are in thermal conductivity with the emitters <b>34</b> and dissipate heat from the emitters to the surrounding environment.

Referring to <figref idref="DRAWINGS">FIGS. 2 and 3</figref>, in the first illustrative embodiment of the light fixture <b>30</b>, airflow cooling channels <b>92</b> are defined by the space between opposite side edges <b>72</b> and <b>74</b> of the emitter housing <b>52</b> and the opposite sides of the rim <b>73</b> and <b>75</b>, and each adjacent fin <b>90</b>. The cooling channels <b>92</b> extend vertically from the bottom rim edge <b>78</b> to the top rim edge <b>77</b> and allow air to flow between the illumination side <b>70</b> and the back side <b>71</b>, for example, typically heating of the housing <b>52</b> would draw air from the illumination side to the back side <b>71</b>. Optionally, the fins <b>90</b> and associated channels <b>92</b> can be parallel, and/or evenly spaced, as shown in <figref idref="DRAWINGS">FIG. 3</figref>.

Additionally, as shown in <figref idref="DRAWINGS">FIGS. 2-4</figref>, in the first embodiment of the light fixture <b>30</b>, the airflow cooling channels <b>92</b> spanning between the opposite rims <b>73</b> and <b>75</b> and edges <b>72</b> and <b>74</b> (<figref idref="DRAWINGS">FIG. 2</figref>), specifically spanning across a back side <b>71</b> of the housing between adjacent fins <b>90</b>, allowing airflow <b>93</b> (<figref idref="DRAWINGS">FIG. 2</figref>) to travel upward from the illumination side <b>70</b> of each side <b>72</b> and <b>74</b> and across the back side <b>71</b>. If the light fixture <b>30</b> is mounted to illuminate upward, for example, against a ceiling (not shown), mounted with the back side <b>71</b> facing downward and the illumination side <b>70</b> upward, then the direction of airflow <b>93</b> would typically be reversed.

Advantageously, the rims <b>73</b> and <b>75</b> provide the added functionality of providing support to the fins <b>90</b> where they extend beyond the left and right side edges <b>72</b> and <b>74</b> of the emitter housing <b>52</b>, more surface area for convective and radiant heat transfer to the surrounding air, and providing a more aesthetically appealing appearance of the light fixture <b>30</b>, limiting the spiny look while retaining the needed cooling fins <b>90</b> projecting beyond the housing <b>52</b> by providing the rim <b>76</b>. For example, the rims <b>73</b> and <b>75</b> conceal portions of the light fixture <b>30</b> because the side edges <b>72</b> and <b>74</b> of the housing <b>52</b> and the fins <b>90</b> do not extend below (in the direction of the illumination side <b>70</b>) an plane <b>94</b> (<figref idref="DRAWINGS">FIG. 4</figref>) formed by the bottom edges <b>78</b> of the rims <b>73</b> and <b>74</b>.

Referring to <figref idref="DRAWINGS">FIGS. 5-7</figref>, a second illustrative embodiment of a light fixture <b>130</b> according to the present invention is illustrated. The features described above for the first embodiment of the light fixture <b>30</b> may also be selectively incorporated in the light fixture <b>130</b>.

Referring to <figref idref="DRAWINGS">FIG. 6</figref>, the light fixture <b>130</b> includes a light source <b>132</b>, including an emitter <b>134</b> and a driver <b>136</b>, an emitter housing <b>152</b>, and a driver housing <b>182</b>. The emitter housing <b>152</b> and driver housing <b>182</b> can be formed from, for example, die cast aluminum or an aluminum alloy. The emitter <b>134</b> can be thermally coupled and mounted to the emitter housing <b>152</b>, and the driver <b>136</b> can be thermally coupled and mounted to the driver housing <b>182</b>. As it typical of commercial lighting fixtures, the emitter housing <b>152</b> may also include components that enclose the emitter <b>134</b> within emitter housing <b>152</b>, for example, including a light reflector <b>154</b>, lens <b>158</b>, and frame <b>160</b>.

The emitter housing <b>152</b> defines an illumination side <b>170</b> (<figref idref="DRAWINGS">FIG. 6</figref>) from which the light source <b>132</b> projects light, an opposite surface or back side <b>171</b>, a bottom side edge <b>172</b>, and a top side edge <b>174</b>. The light fixture <b>130</b> also includes a rim <b>176</b> around the periphery of the emitter housing <b>152</b>, including a bottom rim <b>173</b>, a top rim <b>175</b>, a rear rim edge <b>177</b>, a front rim edge <b>178</b>, and an interior surface <b>179</b>. In the second illustrative embodiment, the bottom rim <b>173</b> is spaced apart from the bottom side edge <b>172</b> of the housing <b>152</b>, the top rim <b>175</b> is spaced apart from the top side edge <b>174</b>, and the remainder of the rim <b>176</b> on left and right sides contacts the housing <b>152</b>.

The light fixture <b>130</b> also includes a plurality of emitter fins <b>190</b>, for example, in the first embodiment defined by the back side <b>171</b> of the emitter housing <b>152</b>, thus, the plurality of emitter fins <b>190</b> are in thermal conductivity with the emitters <b>134</b> and dissipate heat from the emitters to the surrounding environment.

The driver housing <b>182</b> defines surfaces including a front side <b>184</b>, which faces the back side <b>171</b> of the emitter housing <b>152</b>, a top side <b>185</b>, a rear side <b>186</b>, and a bottom side <b>187</b>. Referring to <figref idref="DRAWINGS">FIGS. 6 and 7</figref>, a plurality of driver fins <b>188</b> are defined by the driver housing <b>182</b> and span from the intersection of the front side <b>184</b> and top side <b>185</b>, across the rear side <b>186</b>, to the intersection of the front side <b>184</b> and the bottom side <b>187</b>. The plurality of driver fins <b>188</b> are in thermal conductivity with the driver <b>136</b> and dissipate heat from the driver to the surrounding environment. Each of the driver fins <b>188</b> can be coplanar with respective ones of the emitter fins <b>190</b>, as is shown most clearly in <figref idref="DRAWINGS">FIG. 7</figref>. Referring to <figref idref="DRAWINGS">FIG. 6</figref>, a space <b>196</b> is defined between the rear side <b>171</b> of the emitter housing <b>152</b>, and the front side <b>184</b> of the driver housing <b>182</b>, and will be further referenced below.

As with the first illustrative embodiment, in the second illustrative embodiment of the light fixture <b>130</b>, airflow cooling channels <b>192</b> are defined by the space between opposite side edges <b>172</b> and <b>174</b> of the emitter housing <b>152</b> and the opposite sides of the rim <b>173</b> and <b>175</b>, and each adjacent fin <b>190</b>. The cooling channels <b>192</b> extend from the front rim edge <b>178</b> to the rear rim edge <b>177</b> and allow air to flow between the illumination side <b>170</b> and the back side <b>171</b>. Optionally, the fins <b>190</b> can be parallel, and/or evenly spaced, as shown in <figref idref="DRAWINGS">FIG. 7</figref>.

Additionally, as shown in <figref idref="DRAWINGS">FIG. 6</figref>, in the second embodiment of the light fixture <b>130</b>, the airflow cooling channels <b>192</b> span between fins <b>190</b> through the space <b>196</b>. Specifically, the cooling channels <b>192</b> span between the opposite rims <b>173</b> and <b>175</b> and edges <b>172</b> and <b>174</b>, between and across a back side <b>171</b> of the emitter housing <b>152</b> and front side <b>184</b> of the driver housing <b>182</b>.

Additionally, as shown in <figref idref="DRAWINGS">FIGS. 6 and 7</figref>, the airflow from cooling channels <b>192</b> can flow not only through the space <b>196</b>, but around the driver housing <b>186</b> in the channels <b>198</b> defined by adjacent driver fins <b>188</b>. The channels <b>198</b> can extend fully around the driver housing <b>186</b>, from the intersection of the front side <b>184</b> and top side <b>185</b>, across the back side <b>186</b>, and to the intersection of the front side <b>184</b> and the bottom side <b>187</b>.

While the invention has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as illustrative and not restrictive in character, it being understood that only illustrative embodiments thereof have been shown and described and that all changes and modifications that come within the spirit and scope of the invention as defined in the claims and summary are desired to be protected.